In 1979, before we knew about "the love drug," psychologist Dorothy Tennov coined the term "limerence" to describe the chemical reactions that happen in the brain when we fall head over heels for someone — "crazy in love," so to speak. Regardless of whether the person is a good match for us, the overwhelming download of chemicals into the brain can overpower sanity.

We find ourselves justifying relationships that are unrequited, toxic, or just lacking in fulfillment of basic needs. Over the next four decades of research, Tennov joined poets, playwrights, and pop songs in the conversation about the madness of love.

1. Obsessive thinking about the limerent (that's the object of affection/fixation), which can become intrusive to daily functioning.

2. Irrationally positive evaluations of their attributes and denial of red flags (e.g., "She is a serial murderer, but that's OK. My love will overcome that.")

3. Longing for reciprocation, and when it doesn't happen, fantasizing about it until it becomes reality in your mind.

4. Feelings of ecstasy in the presence of the loved one, even if they are barely aware of you.

5. Deep, wild mood swings, from delight to agony and back again.

6. Total anguish when the relationship ends: not ordinary grief, which accompanies the termination of all relationships, but the feeling that you actually cannot go on living without the person.

7. Unsettling shyness in the limerent object's presence.

8. Extreme exaggeration of any response from the limerent to be interpreted as "a sign" your feelings are requited regardless of actual evidence.

Irrational love — love based on "just a feeling" — can wreak havoc in the lives of people who are otherwise sane and functional. Unfortunately, our culture often promotes these unhealthy behaviors, with songs that are so popular people sing along without really hearing the lyrics.

For example, when Percy Sledge recorded the popular "When a Man Loves a Woman," I wonder how many people actually considered the words he was singing. Here are just a few of the things he refers to:

Can't keep his mind on "nothing else," can't see it, if she's bad, would spend his last dime, would turn his back on his best friend, and would sleep out in the rain. Yikes.

What about "Every Breath You Take" by The Police? The refrain actually says, "I'll be watching you" — every move, every word, every night because, after all, "you belong to me." That's not what healthy, reciprocal love sounds like to me.

Thus, we understand that limerence can refer to an obsessive relationship in which one will behave in ways that might be harmful to him or herself for love's sake (in Sledge's case) or observe and analyze the limerent relentlessly and unwelcomely (much like stalking) as with The Police's protagonist.

Here's some advice to consider if you think you might be under the influence of limerence:

Remember that the strength of your obsessive feelings does not relate to how deeply in love you are. It simply relates to the strength of your limerence.

If you have a pattern of falling in love with the fantasy of a person rather than the reality, you're probably suffering from this state of mind.

1. Keep an honest journal of all of your relationship events — including the disappointing and painful ones, which will give you something with which to challenge your fantasies.

2. If the majority of your friends and family see red flags in your partner that you don't, it could be a sign that what you think is love is actually limerence.

3. Make an objective list of the qualities of a partner who would always be able to support you, even when you don't give him/her what he/she wants, and holds strength in living his/her own life. Do not include feelings. Do not try to make your list match the personality of someone you want to be in a relationship with. Make the list independently of other influences. Then, when you meet new potential partners, you can check your list to see if this person actually has the qualities you know you need in a partner.

4. If your feelings of unrequited love are affecting your daily life and normal functioning, consider speaking with a counselor.

Dorothy Tennov once said, "Limerence is a distinct state that creates that 'feeling of being in love' — that state which Hollywood loves to portray as 'love' ... but limerence is really as far from the genuine article as a zircon is from a true diamond."

A zircon love affair is doomed to break your heart. You are worthy of a diamond.